The present invention relates generally to weight lifting exercise machines, and is particularly concerned with a weight stack frame for mounting a weight stack for linking to exercise equipment on an exercise machine.
Traditionally, weight stacks for exercise machines are mounted in one of two ways, either in-line with the weight stack located either directly in front or directly behind the user, or offset, with the weights located to one side of the user. Exercise machines with in-line weight stacks generally have a footprint that is long and narrow, while machines with an offset weight stack are wider but not as deep. With either design, the footprint should cover as small an area as possible, as square footage is usually at a premium either in a fitness facility or in a home gym environment. If a machine is small, more machines can fit onto the floor space of an exercise facility, and more users can exercise at the same time.
The main advantage to offset weight stacks is the ease of adjusting the weights from the user position. Generally, the user must only reach to the side in order to select the appropriate amount of weight to be lifted. This is true whether the user is performing standing or seated exercises. This is not true of machines with in-line weight stacks. When the weights are mounted in-line and behind the exercise position, the user must reach around to adjust the weights. If seated, the user must get up and walk to the side of the machine in order to adjust the weights. This is inconvenient, and can be a problem in commercial installations such as health clubs, community centers, or the like, where members must wait their turn while the current user is constantly getting up to adjust the weights. For this reason, most commercial exercise machines manufactured today have offset weight stacks.
Weight stacks that are mounted to the side of the user are traditionally belt or cable-driven, and have a cam that the belt or cable wraps around during the exercise movement. The cam is attached to one end of a pivot shaft, and the exercise arm is attached to the opposite end of the shaft. Thus, the cam transfers load or resistance from the weight stack to the exercise arm. The cam is generally mounted on the weight stack frame.
Weight stack frames of various shapes and sizes have been designed in the past. The most common weight stack frame has a pair of straight, vertical and parallel upright struts, and parallel horizontal top and bottom struts to capture the weight stack guide rods on which the weights travel up and down. Another relatively common design is the xe2x80x9cAxe2x80x9d frame, with uprights that angle downward and outward from the top strut at opposing angles.
Generally, pulleys guide the weight stack cable from the top strut of the weight stack frame to the cam. The pulleys are generally mounted in a housing attached either to the top or bottom side of the top strut. In some cases, the pulley housing protrudes from the frame and has one end suspended in mid-air, in order to guide the cable in front of the frame and onto the cam. This places a strain on the welds attaching the housing to the frame, and detracts from the smooth appearance of the frame. Mounting the housing underneath the top strut of the frame also has disadvantages, since any applied force will be transferred to the welds securing the housing to the frame, potentially causing the housing to tear or break away from the strut.
It is an object of the present invention to provide a new and improved weight stack frame which provides for more convenient mounting of the cam.
It is another object of the present invention to provide a weight stack frame with a new and improved pulley housing arrangement.
According to one aspect of the present invention, a weight stack frame for supporting the weight stack of an exercise machine is provided, which comprises a lower horizontal strut, an upper horizontal strut, and front and rear upright struts extending between the upper and lower struts, the upright struts being inclined forwardly at a predetermined angle. The upright struts are preferably parallel to one another.
This provides an angled, forwardly inclined weight stack frame, which permits a cam for transferring load from the weight stack to an exercise station to be located at a more advantageous position on the frame, closer to the frame, so that less stress is placed on the cam mount. The forwardly inclined weight stack frame also provides for the maximum amount of weight stack travel while still having only a relatively small footprint. The frame can accommodate either a forward or rearward mounted cam or exercise arm attachment without needing to reverse the frame.
The frame may be inclined at various angles, although an angle of between 5 and 10 degrees to the vertical is preferred. Preferably, the angled upright struts curve inwardly at their upper ends to join the top strut. A pulley housing may be mounted on the top strut in order to house pulleys for guiding the load-carrying belt or cable to the front or rear of the frame. The housing has first and second ends and a first pulley is located in the first end of the housing at a position above the center of the weight stack, while a second pulley is located at the second end of the housing at a position protruding slightly outwardly from the respective upright strut at the front or rear of the housing. Preferably, the second pulley is at a lower elevation than the first pulley. This arrangement permits the load-carrying belt or cable to be easily directed to the front or rear of the frame, and to the cam mounted on the front or rear upright.
According to another aspect of the present invention, a weight stack frame apparatus is provided, which comprises a frame having upper and lower struts and front and rear upright struts extending between the upper and lower struts, a mounting and guide assembly for a weight stack extending between the upper and lower struts, the upper strut having an upper side, a lower side, a front end and a rear end, and a pulley housing mounted on the upper side of the upper strut, the pulley housing having a first end located over the weight stack mounting and guide assembly and a second end projecting slightly over one end of the upper strut, a first pulley mounted in the first end of the housing, and a second pulley mounted in the second end of the housing, the pulleys comprising means for guiding a load-bearing cable from the weight stack to the front or rear end of the housing.
The pulley housing will be directed forwardly for exercise machines with forward mounted exercise arms, and will be directed rearwardly for exercise machines having rearward mounted exercise arms or devices. In each case, a cam for transferring load to the exercise arm will be mounted on the respective front or rear upright strut, and the load-carrying belt or cable will be directed from the second pulley to the cam, with the belt running as close as possible to the weight stack frame. This reduces the risk of users accidentally coming into contact with the load-carrying belt or cable. The cam may be located directly below the second pulley, or a guide pulley may be mounted on the upright strut for directing the cable or belt from a location directly below the second pulley outwardly to the cam.
Preferably, the pulley housing angles downward from the first end to the second end, to allow the second pulley to rest more closely in the radius of a bend in the frame where the upright strut joins the top strut. This provides a more aesthetically pleasing appearance, as well as keeping the load-carrying belt or cable as close as possible to the frame, and providing good structural support for the housing on the frame, since the housing does not have any portions projecting outwardly from the frame. The closer the belt or cable runs to the frame, the less likely it will be to come into contact with a user or bystander. This is an extremely important safety consideration in unsupervised situations.
In a preferred embodiment of the invention, the pulley housing has spaced side walls and a top wall enclosing the pulleys and load-carrying cable or belt. The top wall provides a safety barrier between the belt and any bystander, and also acts as a guard to reduce the risk of the belt or cable jumping off the pulleys as a result of sudden movement of the exercise arm.
According to another aspect of the present invention, an exercise machine is provided which comprises an exercise arm support frame, an exercise arm pivotally mounted on the exercise arm support frame, a forwardly facing seat for a user using the exercise arm to perform exercises, a weight stack support frame positioned to one side of the seat, the frame having a lower strut, an upper strut, and front and rear struts extending between the lower and upper struts to form an enclosure, a weight stack mounted in the frame enclosure, and a cable and pulley assembly linking a preselected number of weights in the weight stack to the exercise arm, the front and rear struts of the weight stack frame being parallel to one another and being inclined forwardly at an angle to the vertical orientation.
The forwardly inclined weight stack frame of this invention is an improvement over conventional vertical frames or A-frames, in that it allows a more advantageous cam or exercise arm attachment position, closer to the frame, and does not require the frame to be reversed for a rear cam mount. It may also reduce the footprint, or floor area, required to accommodate the exercise machine. The weight stack frame incorporating an angled pulley housing on top of the upper strut permits the load bearing cable or belt to run closer to the frame, reducing the risk of injury as a result of a user or bystander coming into contact with the cable or belt.